Heat exchanger



Jan. l1,v 1938. Q R P|EPER 2,104,813

` HEAT EXCHANGER Filed July 20, 1936 4 Sheets-Sheet 1 Jan. 11, 1938.

C. PIEPER HEAT EXCHANGER 4 sheets-sneu 2 Filed July 2o, 1956 AH-IE INVENTOR. CHESTER A. P/EPER Jaun.A 1-1, 1938.

C. R. PIEPER HEAT EXCHANGER Filed July 20, 1936 4 Sheets-Sheet 3 INVENTOR. CHESTER l?. P/EPER Jan. 11, 1938. v C R. .DIEPER y 2,104,813

HEAT EXCHANGER Filed July 20, 1936 4 Sheets-Sheet 4 INVENToR. CHL-'STER R. P/EPER rToRNEY.

-lPatented Jan. ll, 1938 HEAT EXCHANGER Chester R. Pieper, La Crm Wis.

Application July 20, *1936, Serial No. 91,495

15 Claims.

My invention relates to heat exchangers; and more particularly to an improved heater of the type in which heat from a supply of hot water is transferred to a stream of air. My improved device is especially applicable for heating the interior of automotive vehicles, the fluid utilized for cooling the engine being readily available for circulation through the heater where it serves as the heating agent.

An object of .my invention. is to provide. a heater of the character described which is simple in -design and construction, economical of manufacture, and highly efcient in operation.

Another object of my invention resides in the provision of an improved water-heated airheater of compact, rugged construction, which requires only a small mounting space, and is cay pable of withstanding high internal pressures as well as the deleterious effects of jar and vibration.

Yet another object of my invention is attained in the provision of an improved heater in which air is impelled through a multiplicity of passages defined by heating surfaces, the formation and course of the passages being such that the flow of air therethrough is not unduly impeded, yety which provide extensive heating surfaces confined in a relatively small space.

A further object ofmy invention is to provide in combination with a heater of the character described, improved, simplied means for controlling and directing the air-as it issues from the heater.

Yet a further object Aof my invention is to provide, in combination with a water-heated airheater embodying an electrically driven fan, or impeller for obtaining positive circulation Vof air through the device, of improved manual and automatic means for controlling the operation of the impeller and coordinating its operationv with the temperature of the heating Iluid and the temperature of the air to be heated.

My invention resides in the construction, shape, configuration and arrangement of the various parts, openings and passageways which provide fan motor; Fig. is a front view of the manipulating element and dial for the control means; Fig. 6 is a rear view of the inner member which constitutes a water chamber, showing the air impeller as positioned relative thereto; Fig. 7 is a iront view of the inner member; Fig. 8 is a sectional view through the innerrmember, taken at line 8-8 of Fig. 6; Fig. 9 is a sectional side elevation of a heater assembly of modied form but generally similar to the heater illustrated in Figs. 1 et seq.; and Fig. 10 is a fragmentary sectional view throughA the heater illustrated in Fig. 9 and taken at line lil-lil of that ligure.

Referring lnow by characters of reference to the drawings, my improved heater comprises an inner member l2 which provides a chamber for hot water or other fluid constituting the heating medium, the fluid being conducted through a supply conduit l I3 to the inner member I2, where it gives up part of its heat, and is conducted from vv"the'member i2 at a lower temperature through discharge -conduit I d. The flow of iluid through member l2 may be induced solely by reason of the temperature differential existing between the fluid in the upper inlet passage and that in the lower outlet passage, in accordance with Well known principles of convection currents, or such flow may be augmented by the provision of a vpump (not shown) in the uid circulating system. When the device is installed in an automotive vehicle propelled byra watercooled motor, the conduits i3 andl may be suitably connected into thev water circulating system so as to utilize the water pump, customarily'provided in connection with such systems,V for inducing a positive ow' of fluid through member l2.

Enclosing member I2 is a casing or jacket member l5, the walls of which are spaced from the walls of member I2 to provide a heating passage `of air. Inlet and outlet openings for the air, designated I6 and I'I respectively, are located in the rear and front walls I8 and I9 of jacket .l

member I5. An air impeller 20 located adjacent;

tioned, the inner, water-receiving member I2 is. of relatively fiat, circular shape and may be well described as a hollow, thin-walled, substantially discoidal member. or otherwise formed as an integral member as shown, preferably of a light-weight metal `having Side of the inner member.

good heat conducting properties, aluminum or aluminum-alloy being satisfactory for the purpose.- Inlet and outlet openings 23 and 24 for the heating fluid are located dlametrally at the upper andlower margins of the inner member, preferably in the rear wall 25 thereof. Threaded nipples 26 at the openings 23 and 24 accommodate the ends of conduits 'I3 and I4 and provide for a fluid-tight connection between the conduits and the inner member. The interior of the inner member maybe provided with suit` able baiiies or partitions (not shown) to increase the path of travel of, and contact with the heating fluid.

The central portion of the forward wall 21 bulges outwardly and mergesinto an outwardly projecting boss 28, which formation aids in directing air, flowing toward the center along the lforward wall, axially outwardly throughnthe air outlet opening I1. The rear wall 25 of the inner member may be dished inwardly as shown, for purposes of enlarging the air intake space, and providing increased space for the impeller 2li.

Referring now toFigs. 6` and 'l as well as to Fig. 1, the inner member isvprovided with a series of heat radiating iins designated which are joined edgewise to the outer surface of the inner member. The iins 3|) extend with radial trend from the center to the periphery of the forward wall 27 (Fig. 7) thence over the circumferential wall and inwardly toward the center along the rear wall 25 of the inner member. The fins do not extend completely to the center of the rear wall 25 but terminate at points spaced from the center, thus providing a space to accommodate the rotary imp eller 20, as best appears from Fig. 6. Auxiliary ns 30a are disposed in the spaces or air passages formed between fins 30 and Vserve The heat radiating fins thus described may extend rectilineally and with true'radial trend from the center to the peripheral margins of the inner member. It is my preference, however, to have the fins extend with spiral trend from the center to the peripheral edge on one side wall of the inner member, the spiral trend of the fins continuing in the same direction on the opposite 'Ihis will be clearly understood by referring to Fig. 7, wherein dotted lines indicate the trend of a plurality of fins on the side of the member I2 opposite to thatwhich is shown.

The purpose andV advantages of the preferred ffin arrangement is twofold. The length vof theair 75,.' The casing or jacket member IS-,conforms in It may be cast, die-pressed,v

shape with thatA of the inner member I2, and accordingly may be described as substantially discoidal. For ease of manufacture and assembly, the jacket I5 is preferably formed of a pair of complemental sections, joined together along circumferential edges as appears in Fig. 1. One of such sections is provided with an offset annular flange or lip 3| which fits over the peripheral margin of the mating section, producing a substantially airtight joint. The sections are -mounted over the ns 30 and 30a and supported by the 'clins in spaced relation to the inner Lmember I2. A pair or more of screws 32 (Fig. 3)

serve to maintain the sections inassembled relation, yet permit the same to be readily disassembled for purposes of cleaning.

Located centrally, or axially in the rear and front walls I8 and I9 of .the jacket I5 are the air inlet and outlet openings I6 and I'I, respectively, previously mentioned. The inlet opening .I6 is preferably circular and of such size that the marginal portions of the rear wall I8 which surround the opening' extend toward the center beyond the ends of the i'lns, and completely shield the impeller blades 33, to be hereinafter described.

Extending rearwardly from wall I8 at the edge of the inlet opening is a pair of bracket arms 34 by which the impeller motor 2l is supported. The arms 34 terminate in a circular band 35 which embraces the motor 2|,.a shoulder 36'on the moassembly may be conveniently mounted on the dashboard 38, or on any other suitable support, by means of the conduits I3 and I4, and clamping nuts 39 threaded thereon.

'Ihe air impeller designated generally at 20 comprises a disc 40 which may be dished to conform to the shape of the central part of wall 25. A hub portion 4I on the disc 40 receives the motor shaft, and is secured thereto by means of .a set screw. The impellerv blades 33 project from one side of the-disc and are disposed substantially at right angles thereto. Further, the blades are preferably positioned angularly with respect to the radii of the disc so that they tend to sweep the air into the mouths of the passages formed between the fins.

It will now appear that rotation of the impeller in the direction indicated by the arrow in Fig. 6 causes air to be drawn into the jacket through opening I5, then impelied with rotary as well as centrifugal movement into the air passages.-

The mouths of the passages, being directed toward the reaction surfaces of the impeller blades and being of the same trend as that with which the air leaves the blades, receive the air with minimum turbulence.

The control and deilecting means located adjacent the outlet opening I1 comprises the con- Vcavo-convex plate 22 having an axial, tubular extension 43 which receives, and frictionally embraces the tubular arm 44. The inner end of arm `44 is mounted on the boss 28 in such manner as to be adjustable angularly with respect to the heater axis, in all planes defined by the axis of the heater. For this purpose the boss 2l has a spherical surface upon which is seated the flared end portion. of-arm 44, such end portion being shaped to conform to the boss. A conical recess flin the boss receives one end of a spring 41, which spring-end is secured to the boss at the pivotal center of arm 44. The spring extends is of itself angularly adjustable, the plate may bel` positioned to control and deect the heated air issuing from the outlet opening upwardly, downwardly or laterally. The control plate 22 may be ,adjusted to close completely the opening H by moving the plate into engagement with the annular lip 59 which skirts the opening.

I now describe my preferred means for manually and automatically controlling the operation of the impeller motor, the automatic control serving to correlate motor operation with such temperature conditions of the heating uid and the air to be heated as make the same expedient. The electrical control means include a pair of thermally responsive switchesV which are con.- nected in series circuit relation with each other and with the impeller motor. One of such switches is constructed and arranged to be operatively inuenced by the temperature of the fluid in the outlet conduit l5.' When the fluid, after having passed through the inner member l2, has attained the desired, predetermined temperature, this switch automatically closes. The switch is adjusted so that it will close when there is sufcient heat in the fluid to affect materially the temperature of the air passing through the heater. When the temperature of the uid drops below the point corresponding to this heat value, the switch automatically opens. Obviously, under normal conditions of use it would be an inexpedient waste of electrical energy to have the impeller motor operate when the device cannot function as a heater becausel of insumcient heat in the heating huid.

The other switch is constructed and arranged I so as to be influenced by the temperature of the lmentioned switch.

air after the same has circulatedsthrough the space to be heated', the automatically operable switch arm of this switch being situated in the air path near the intake opening I6. Whenv the temperature of the air reaches a desired predetermined point, this switch, previously in closed condition, automatically opens' the circuit to suspend motor operation until the switch recloses the circuit as a consequence of a drop in air temperature. Motor operation depends, of course, also upon the open or closed condition ofthe rst Means are provided for manually presetting the second switch to open and close at any desired air temperature to maintain, automatically, comfortable conditions within the space to be heated. By such means the circuit may also be interrupted manually to render the impeler motor inoperative irrespective of temperature conditions.

' Referring to Figfl, the switching assembly is mounted in a suitable housing which is preferably formed of bre, moulded plastic' or other material having good electrical and thermal insulating properties. The switch, rst mentioned above, comprises a bimetallic strip 5I which issecured at one end to an insulating base 52 and extends therefrom along, spaced from, butin close proximity to conduitA I4. The stripfr switch arm.

stress in the same.

5| becomes warped when heated by the water in conduit Il and when'the proper temperature is reached it contacts switch arm 53, comprising one arm of a substantially U-shaped, resilient metal strip. The other arm of such strip -'provides the manually adjustable switch arm 5l of the .second switch and cooperates with the bi-metallic switch arm 55. The arm 55 has itsmajor part situated exteriorly of the housing 50 and in the path of the air near the intake opening of the heater. Ac-r cordingly this thermal-responsive arm 55 'is adapted to be influenced by the temperature of the air flowing into the heater.J The housing 5l! and vfins 56 thereon shield the arm. 55 from heat emanating from pipe I6, and consequently heat directly` therefrom does not materially influence the operation of the switch 55.

Y Under normal operating conditions the forward end 51 of arm 55 contacts arm 53 and tends to move downwardly away from arm 54 with rising temperatures. A cam 58 having a spiral camming surface operatively engages arm 55 to raise and lower the same, the arm, due to its inherent resiience, maintaining itself in engagement with the cam. Cam 55, preferably of insulating ma.- terial, is mounted on one end of a shaft 59 which is supported by a bearing arm 6B and projects through the forward wall El of the housing 5D. A manipulating knob 52 is secured to the forward end of the shaft and is suitabiy marked to indicate the position at which it may be pre-set to cause interruption of the impeller circuit when the temperature in the space to be heated has attained the selected, pre-set degree. By way of example,

assume that the knob`52 has been set to place L the 80 degree mark in registration with a suitable mark such as an arrow on the front face of wall 6I. This setting causes arm 51 to be displaced by cam 58 into its lowerrnost position (see Fig. 4). The bi-metallic arm 55 is aso forced downwardly which produces an initial Electrical contact between arms 55 and 55 will not be broken until the temperature of arm 55 is raised suiciently, rst, to set up warping stresses which equal the said initial stress', and thereafter (at 80 degrees) to move the arm out of contact with arm 5E. When the manipulating knob is set at degrees, the initial stress produced in arm 55,' and hence the temperature at which such initial stress is oqualized before breaking contact with arm 54, is

proportionately less than the condition existing' by reason of. -the degree setting. l

The manipulating knob may also be set in an off position (Fig. 5)' whereby arm Ed'is allowed to move to a position upwardly beyond the uppermost limit of travel of the contact surface of arm 55, which contact surface is prevented from following arm 56 by means of a stop member .53.

Thus the circuit may be broken to stop motor t operation regardless of the temperature conditions of the heating uid and air.

Considering the operation of the heater when installed inan automobile, and with. the control knob 62 set, say at 70 degrees, when the driver stops the engine, the impeller motor will normally continue operating until the temperature of the iiuid in conduit I4 drops su'ciently'to cause interruption of the impeller motor circuit at switch arms l5I and 53. Thus, if the driver does not desire, or forgets to lturn o the impeller motor immediately with the engine, the motor is turned off automatically shortly afterengine operation ceases. The driver may, however, stop the impeller motor when he turns off his engine by moving the manipulating knob 62 to oif position.

The mo-died heater illustrated in Fig. 9 is similar in general construction and operation to the heater previously described, but distinguishes from the described heater in that it is designed to utilize eiliciently a larger amount of heating uid, and to provide increased heat radiating surfaces. In short, the heater of Fig. 9 is more suitable where the space to be heated is great.

Thus, the inner fluid-receiving member previously described as discoidal has a hollow annular projection 64 which increases the iiuid capacity of the member. Inlet and outlet iluid-conduit-s i3 and i4 are connected to' the projecting portion 64 in diametrally opposite relation at the rear extremity thereof. The jacketing member likewise is provided with a portion 65 which encloses .the projecting portion 64 of the inner member. Heat radiating ns E6 extend between the projecting portions of the members, as best appears in Fig. 10. The air and iiuid paths through the heater are indicated by arrowsin Fig. 9.

Having described my invention Iwith reference to two practical, simple and economical embodiments/thereof, it should be understood that various changes may be made in the construction and arrangement of parts herein yshown and described Without departing from the spirit and full intended scope of my invention as the same is fairly construed by the appended claims.

I claim:

1. A heater comprising a hollow, substantially discoidal member having fluid inlet and outlet openings and a series of outwardly projecting lns of substantially radial trend thereon, a jacket member mounted over said ns and with the discoidal member forming an air passage, and

air inlet and outlet openings in said jacketing member.

2. A heater comprising a hollow discoidal member having fluid inlet and outlet openings, a series of ins projecting outwardly from opposite sides of said member and extending with a substantially spiral trend, from the center to the periphery thereof, a jacket member mounted over said ns, and air inlet and outlet openings in said jacket member located centrally withrespect to said discoidal member.

3. A heater comprising a. hollow, substantially discoidal member having water inlet and outlet openings, said member having an outwardly projecting air dilecting portion located centrally at one side thereof, a jacket having walls spaced from said member to provide an air passage around the same, said jacket-having an air outlet opening facing said `air defiecting portion of the member and an air inlet opening having air propelling means adjacent thereto.

4. A heater comprising a hollow, substantially discoidal jacket member having air inlet and'air outlet openings located centrally in relatively opposite sides thereof, a hollow, substantially discoidal water chamber having inlet and outlet openings spaced within and coaxial of said jacket member, the space between said members' constituting a passage interconnecting the air inlet and outlet openings, and a plurality of iins for directing air in a Substantially helical course through saidpassage. v

5. A heater comprising a hollow, substantially discoidal member having water inlet and outet openings, one side of said member having an' o ward bulge at the center thereof, a jacket enclosing said member having wall portions spaced l l from the walls of said member, the space between lthe walls ofsaid member and jacket constituting an air passage, an air inlet opening in said jacket, and an air outlet opening in said jacket adjacent the bulge on said member.

6. A heater comprising a pair of hollow, substantially discoidal members, one thereof being spaced centrally within the other and constituting a water chamber, the space between said members constituting a passage for air to be heated, inlet and outlet openings in the inner member located diametrally in one side thereof,

inlet and outlet openings for air located laxially in relatively opposite sides of the outer member,

and a series of iins in the air passage for dividing the air passing therethrough into a multiplicity of individual streams.

7. A heater comprising a fluid-receiving heating element, a casing member disposed about said element and spaced therefrom to provide an air passage between thev element and casing, air inlet and outlet openings in said casing, means adjacent said inlet opening for impelling air through said passage, and air-controlling and deiiecting means adjacent said outlet comprising an arm projecting axially through the outlet opening and adjustably secured atits inner end to the heating element, and a deflecting plate mounted on said arm and adjustable therealong. 8. A heater comprising a hollow, substantially discoidal member having water inlet and outlet openings, said member bulging outwardly at the center of one side thereof, avjacket having walls spaced from the walls of said member to provide Y an air passage therebetween, air inlet andoutlet openingsin said jacket located axially with respect to said discoidal member, and a series of iins in the air passagefor dividing the air passing therethrough into a multiplicity of individual streams. Y

9. A heater comprisinga pair of hollow, substantially discoidal members, one thereof being spaced within the other and constituting a water chamber, the space between themembers constituinng a passage for air to be heated, said inner member having diametrally located water inlet and outlet openings, one side of said inner member bulging outwardly at the center thereof; inlet` and outlet openings for air located axially in opposite sides of the outer member, and a series of outwardly projecting 'ilns formed on the inner member for dividing air passing between the members into a multiplicity of individual streams.

10. A heater comprising a pair of hollow, substantially discoidal members, one thereof being spaced within the other and constituting a water chamber, inlet and outlet openings in the inner member, inlet and .outlet openings for air located axially, in relatively opposite sides of the `outer member, arseries of ilns dividing the space between said members into a' multiplicity affair passages, and an air impeller adapted to force air centrifugally into said air es, disposed within theouter member.

11. A heater comprising a pair of hollow, substannauymscoidal members, one thereof being air passages. and means for forcing air through said passages including a rotary impellerv disposed within the outer member adjacent the air inlet opening.

12. In a heater including a jacket member having an air outlet opening, means for controlling the air at said outlet opening, said means including a shaft projecting outwardly through said opening and mounted at its inner end, for adjustable -rocking movement, and a. plate mounted for adjustable sliding movement along said shaft. l

13. In a heater including a pair of hollow, substantially discoidal members, one thereofv being spaced internally of the other and constituting a water chamber, inlet and outlet openings for air located axiallysin relatively opposite sides of the outer member. an air impeller adjacent the inlet opening and air controlling means adjacent the outlet opening. said means comprising an arm mounted for pivotal adjustment on the inner member and projecting outwardly through the air outlet opening, and a deecting and closure plate mounted on said arm for adjustment therealong.

14. In a fluid-heated air-heater, a hollowwalled, substantially cup-shaped member adapted to receive heating fluid in the wall space thereof, uid inlet and outlet conduits communieating with the wall space, a jacket member spaced about the uid-receiving member, said jacket member being of shape conforming to thatof the fluid-receiving member and having air inlet and outlet openings located axially in opposite walls thereof, and an air impeller disposed adjacent the air inlet opening.

15. An automobile heater of uid-heated circulating air type, comprising an inner, substantially cup-shaped member having hollow walls adapted to receive thevheating fluid therein, fluid inlet and, outlet conduits connected at diametrally opposite points to the rim of said inner member, said inner member ,having-a series of heat radiating ns on the outer surface thereof; a jacket member of shape conforming to that of the inner member, mounted overA said ns, said jacket member having air inlet and outlet openings located axially in'opposite walls thereof, an air impeller disposed within the jacket member adjacent the 'air inlet opening, and adjustlable air deecting means disposed adjacent the air outlet opening.

CHES'IER R. PIEPER.A 

